In a cellular telecommunication system as illustrated in FIG. 1, like a UMTS or LTE system, a plurality of secondary stations 110a-d like User Equipments, communicate within a cell 100a with the primary station 101a operating the cell. In such a system, the primary station 101a and the secondary stations may each comprise an antenna array comprising a plurality of antennas. These antennas may be used to communicate in a MIMO mode by beamforming. Complex coefficients applied on the transmitting antennas of the transmitting station, here the primary station 101a and/or on the receiving station, here the secondary stations 110a-d enable the creation communication streams each of which are associated with one or more spatial channels.
In order to provide to the primary station 101a with knowledge of transmission conditions experienced by the secondary stations so that a suitable transmission mode is selected, the secondary stations may measure some parameters like attenuation, SINR, interference etc. . . . . Then, the secondary stations may feedback reports representative of these conditions like an achievable data rate (as in CQIs) or indication of propagation loss.
However, the secondary station computes this kind of feedback on the basis of its local measurements, although it has no overview of the network nor of the whole system resources.